CISCO Security Advisory
Published Date: Not specified
CVE: CVE-2026-20349
Advisory Summary
🔷 Title: Cisco Secure Firewall & ASA/FTD Remote Access SSL VPN DoS Vulnerability (CVE-2026-20349)
- Cisco disclosed a High-impact vulnerability in the Remote Access SSL VPN service affecting Cisco Secure Firewall ASA software and Cisco Secure Firewall Threat Defense (FTD) software.
- A remote attacker without authentication can send a crafted HTTP request that triggers insufficient error checking, causing the device to reload unexpectedly.
- Result: Denial of Service (DoS)—availability impact for VPN access and potentially related security services during reload.
- SSL VPN endpoints are often exposed to the internet; an unauthenticated trigger makes exploitation operationally feasible for attackers.
- Reload behavior can interrupt VPN sessions and degrade service continuity, which is especially risky for incident response, remote workforce access, and branch connectivity.
- Internet-exposed SSL VPN: Higher probability of exploitation attempts.
- Lack of timely patching: Sustained exposure window until updates are applied.
- Operational fragility: Devices may cycle/reload under attack conditions, compounding outages.
- Look for unusual spikes in Remote Access SSL VPN traffic or abnormal HTTP request patterns targeting the VPN service.
- If you have maintenance constraints, coordinate a controlled rollout and monitor for reload/restart events while applying updates.
- Vulnerability: Remote Access SSL VPN insufficient error checking leading to reload-based DoS
- CVE: CVE-2026-20349
- Impact rating: High
- Workarounds: None
Reference: Vendor Advisory